Information from patients with severe mental illness (SMI) is essential for accurate diagnosis, effective monitoring, and research to improve services. Despite reports of elevated risk for HIV and other sexually transmitted diseases (STDs) in this population, risk and disease status are inadequately assessed. Self-report data are crucial for this assessment. Studies by our group and others have shown that substance use disorders and posttraumatic stress disorder (PTSD), contribute to HIV risk, are prevalent in people with SMI, but are rarely noted on admission. Similarly, HIV and other STDs often go undetected in mental health services settings. Current research by our consortium has underlined the problems of assessment of risk behavior for HIV/AIDS and other STDs including interviewer reluctance and patient underreporting. Systematic assessment of risk status and co-morbid conditions is needed for effective intervention. Computerization is proceeding in the field, but patient input continues to be collected in an expensive, time-consuming manner. Service providers and researchers often use trained interviewers to collect data from patients. They believe that interviewers are essential for overcoming potential literacy problems, translating ambiguous language, and using nonverbal information to facilitate data collection. These reasons have rarely been subjected to investigation. There are liabilities to the use of trained interviewers: interviewer reluctance, high cost, lack of uniformity, inhibition in answering sensitive questions, and possible subjectivity. We propose a study comparing trained interviewers and computer- assisted interviews (CAI) for obtaining self-report on HIV risk and co-morbid conditions from patients with SMI. The CAI includes speech and uses the internet. We will collect data on gender, age, and number of recent hospitalizations and on several scales: the AIDS Risk Inventory (ARI), the Dartmouth Assessment of Lifestyle Instrument (DALI, a substance abuse screen), the PTSD Checklist (PCL), and a questionnaire on patient preferences. These scales were chosen because they stress different aspects of self report and because they are related to the prevalence of HIV and other STDs in this population. We plan to measure patient attitudes, reliability, intercorrelations, completion rates, and amount of information divulged. We have criterion measures of substance abuse for the DALI and hospital utilization, allowing us to compute criterion validity for those measures. The data will supplement two ongoing research projects investigating HIV/AIDS and risky behaviors in people with SMI.